For decades, nearly all air handlers were composed of the same components: an air blower, a heat-exchanging coil, and a housing. However, due to recent advancements in electronics, most purely mechanical devices are now seeing electronics being included in the units. Electronic control circuits are being put into many devices in order to increase, e.g., the reliability of the device. In some air handlers, for example, electronic control units are being installed to give customers more options for controlling their air handling units.
In addition to these components, air handling units sometimes contain a drain pan. The drain pan is usually placed underneath the heat-exchanging coil in order to collect condensation from the heat-exchanging coil and the surrounding housing interior. After collecting condensation, there is usually a drain in the drain pan that allows collected condensation to exit the pan.
Traditionally, the air blower would be located at the top of a small box air handling unit, the heat-exchanging coil would be located underneath the air blower, and the drain pan would be located at the bottom of the small box air handling unit just below the heat-exchanging coil.
Unfortunately, traditional drains can often fail to properly remove collected condensation. One reason that traditional drains have failed was because algae or mold would grow in the moist environment inside the housing, and would clog the drain. Afterwards, the condensation would continue to collect within the drain pan, and eventually would overflow over the sides of the drain pan in an uncontrolled manner. In older units, the overflow was not as great a problem since the drain pan was usually located at the bottom of the small box air handling unit. That is, there was nothing underneath the drain pan to become damaged from the overflow, except for things immediately outside the unit itself.
A new issue, however, has occurred since the introduction of electronics into air handling units. Electronics, and many other water-sensitive elements, cannot operate correctly if collected condensation spills over onto the electronics itself. Unlike traditional air handling units, new electronic-based air handling units are filled with, e.g., electronic control devices placed throughout the housing itself. Thus, these electronic control devices, along with other water-sensitive elements (e.g., an air blower, an electronics or electrical component, electrical connector), are in jeopardy of being damaged when water overflows from a clogged drain pan. Furthermore, given the nature of air handling units, and the fact that they may be changed in orientation, it is possible that these water-sensitive elements could end up underneath the drain pan.
It would therefore be desirable to provide a way of emptying overfilled collected condensation from the drain pan in a way that would not disturb the electronics or the air blower, or any other water-sensitive device that may be installed within the air handling unit.